Bug#27306178: ERROR IN SERVER HANDSHAKE WHILE CONNECTING

              WITH AUTH_SOCK PLUGIN USER

Post push fix: Fixing 5.7 test issues.

(cherry picked from commit 5c32d17f7d552acc1db9e52260f7d2601e0f1929)

Author: harinvadodaria

mysql-test/suite/auth_sec/include/multiple_plugins.inc

@@ -52,8 +52,6 @@ FLUSH PRIVILEGES;
 --echo # Change user tests
 
 --connect(qa_test_1_conn, localhost, qa_test_1_user, qa_test_1_dest,,,,SSL)
---change_user native, abcd
-SELECT CURRENT_USER();
 --change_user sha256, abcd
 SELECT CURRENT_USER();
 --change_user
@@ -70,8 +68,6 @@ SELECT CURRENT_USER();
 --connect(sha256_conn, localhost, sha256, abcd,,,,SSL)
 --change_user qa_test_1_user, qa_test_1_dest
 SELECT CURRENT_USER();
---change_user native, abcd
-SELECT CURRENT_USER();
 --change_user
 SELECT CURRENT_USER();
 

mysql-test/suite/auth_sec/r/multiple_plugins.result

@@ -55,9 +55,6 @@ FLUSH PRIVILEGES;
 # Change user tests
 SELECT CURRENT_USER();
 CURRENT_USER()
-native@localhost
-SELECT CURRENT_USER();
-CURRENT_USER()
 sha256@localhost
 SELECT CURRENT_USER();
 CURRENT_USER()
@@ -76,10 +73,7 @@ CURRENT_USER()
 qa_test_1_user@%
 SELECT CURRENT_USER();
 CURRENT_USER()
-native@localhost
-SELECT CURRENT_USER();
-CURRENT_USER()
-native@localhost
+qa_test_1_user@%
 # Drop users
 DROP USER qa_test_1_user;
 DROP USER qa_test_1_dest;
@@ -142,9 +136,6 @@ FLUSH PRIVILEGES;
 # Change user tests
 SELECT CURRENT_USER();
 CURRENT_USER()
-native@localhost
-SELECT CURRENT_USER();
-CURRENT_USER()
 sha256@localhost
 SELECT CURRENT_USER();
 CURRENT_USER()
@@ -163,10 +154,7 @@ CURRENT_USER()
 qa_test_1_user@%
 SELECT CURRENT_USER();
 CURRENT_USER()
-native@localhost
-SELECT CURRENT_USER();
-CURRENT_USER()
-native@localhost
+qa_test_1_user@%
 # Drop users
 DROP USER qa_test_1_user;
 DROP USER qa_test_1_dest;

sql-common/client.c

@@ -6219,16 +6219,29 @@ static int native_password_auth_client(MYSQL_PLUGIN_VIO *vio, MYSQL *mysql)
 
   DBUG_ENTER("native_password_auth_client");
 
-  /* read the scramble */
-  if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
-    DBUG_RETURN(CR_ERROR);
 
-  if (pkt_len != SCRAMBLE_LENGTH + 1)
-    DBUG_RETURN(CR_SERVER_HANDSHAKE_ERR);
+  if (((MCPVIO_EXT *)vio)->mysql_change_user)
+  {
+    /*
+      in mysql_change_user() the client sends the first packet.
+      we use the old scramble.
+    */
+    pkt= (uchar*)mysql->scramble;
+    pkt_len= SCRAMBLE_LENGTH + 1;
+  }
+  else
+  {
+    /* read the scramble */
+    if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
+      DBUG_RETURN(CR_ERROR);
 
-  /* save it in MYSQL */
-  memcpy(mysql->scramble, pkt, SCRAMBLE_LENGTH);
-  mysql->scramble[SCRAMBLE_LENGTH] = 0;
+    if (pkt_len != SCRAMBLE_LENGTH + 1)
+      DBUG_RETURN(CR_SERVER_HANDSHAKE_ERR);
+
+    /* save it in MYSQL */
+    memcpy(mysql->scramble, pkt, SCRAMBLE_LENGTH);
+    mysql->scramble[SCRAMBLE_LENGTH] = 0;
+  }
 
   if (mysql->passwd[0])
   {